Architectural Design
January 15, 2024
The least visible but most critical part of a villa is its foundation. Foundation errors reveal themselves years later as cracking, settlement and earthquake damage. Choosing the right foundation type and planning costs realistically is therefore essential.
Foundation Types and Their Applications
Pad foundation: the simplest and most economical solution applied individually beneath each column on firm, homogeneous ground. Strip foundation: connects multiple columns in a continuous beam; widely used in medium-quality ground conditions. Raft (mat) foundation: a single concrete slab covering the entire footprint of the building; equalises settlement on variable or soft ground and reduces risk. Piled foundation: when near-surface soil is inadequate, load is transferred via deep reinforced concrete piles to bearing strata below; the most expensive but essential in certain conditions.
2025 Foundation Cost Estimates
Approximate cost ranges for a 200 m² villa (2025, Istanbul region): Pad or strip foundation: 150,000–280,000 TRY; Raft foundation: 400,000–700,000 TRY; Piled system: 600,000–1,200,000 TRY; Basement additional items (excavation + retaining wall + waterproofing): 350,000–600,000 TRY. These figures cover geotechnical survey, excavation and concrete costs and can vary significantly with ground conditions.
No Foundation Selection Without a Geotechnical Survey
A geotechnical investigation uses borehole drilling, sampling and laboratory testing to establish the soil's bearing capacity, liquefaction risk and compressibility. Without this report, an engineer cannot determine the foundation type on a scientific basis. Also mandatory for the permit application, a geotechnical survey for a 200 m² villa costs 15,000–35,000 TRY in 2025. Cutting this cost risks a far more expensive ground-improvement or strengthening bill later. At Home Yapı Mühendislik, we treat the geotechnical survey as a mandatory first step in every project.
Structural Engineering